The deal beats Huddersfield's previous record transfer, which was the £1.8m they paid for Christopher Schindler last year.

Mooy began his professional career with Bolton Wanderers and had a spell at St Mirren in Scotland before returning to his native Australia.

He was a key figure in Huddersfield's return to the top division after a 45-year absence and manager David Wagner said at the end of the season that he was keen to keep him at the John Smith's Stadium.